Construction of aqueous supercapacitors with oxidation suppression of nickel phosphide via interfacial engineering and electric field modulation for enhanced secondary energy storage

Abstract

The Ni₂P@NiCo-LDHs material was successfully synthesized via elaborately designed interface engineering. First-principles calculations confirmed the formation of the heterojunction, and the d-orbital centers of Co and Ni were modulated to achieve the synergistic optimization of oxidation inhibition and pseudocapacitive activity. In a three-electrode system, the electrode with the best performance achieved a specific capacitance of 1001.4 F g⁻¹ at a low current density and demonstrated obvious secondary energy storage during the test. In practical applications, the assembled asymmetric supercapacitor achieved a power density of 766.81 W kg⁻¹ and an energy density of 51.88 W h kg⁻¹ within a voltage window of 1.7 V. After 10 000 cycles, the capacitance retention rate reached 96.3%. This underlines the broad prospects of designing heterojunction materials with oxidation inhibition and dual energy storage through interface engineering in the energy storage field.